Expandable sealing mechanism

ABSTRACT

A sealing assembly has an expansion band having an arcuate band portion and a pair of threaded end portions formed at opposing ends of the arcuate band, in which the arcuate band and threaded end portions are monolithically formed as a single piece. Fixed within respective threaded end portions are a pair of oppositely threaded nuts adapted to receive a bolt having correspondingly oppositely threaded ends. Rotation of the bolt causes the threaded end portions to be simultaneously driven apart or drawn toward one another (depending on the rotation direction of the bolt) to thereby expand or contract the overall outer profile of the arcuate band portion. The monolithically formed expansion band may be made of an inexpensive, non-rusting material such as nylon 66, and glass fibers and/or additives may be employed to impart strength and flexibility.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit under Title 35, U.S.C.Section 119(e) of U.S. Provisional Patent Application Ser. No.61/751,056, filed Jan. 10, 2013 and entitled EXPANDABLE SEALINGMECHANISM, the entire disclosure of which is hereby expresslyincorporated herein by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to an expandable sealing mechanism, andassociated method, for sealingly compressing a gasket or seal against anannular wall of a rigid structure. More particularly, the presentdisclosure relates to sealing structures and arrangements for sealinglyconnecting an opening in a manhole wall to a pipe entering or exitingthe manhole wall through the opening.

2. Description of the Related Art

In underground pipe systems, it is often necessary to connect a pipe ina sealed manner within an opening in the wall of a rigid structure, suchas a manhole wall. Typically, a flexible elastomeric seal or gasket isplaced within the opening in the wall, followed by fitting an expansionring against the interior surface of the gasket. Thereafter, a suitableexpansion mechanism is used to radially expand the expansion ring andlock same in an expanded condition in which the gasket is sealinglycompressed between the expansion ring and the opening in the wall of thestructure. A pipe is inserted through the gasket, and one or moreexternal clamps are installed around a portion of the gasket whichextends from the wall to sealingly compress the extending portion of thegasket between the clamps and the outer surface of the pipe. In thismanner, a sealed connection is made between the pipe and the structure.

An alternative application for a sealing device including agasket/expansion ring combination is underground pipes which are used inmunicipal water and sewer systems, for example. Such underground pipestypically include bell and spigot ends that are attached to one anotherin a sealed manner. Typically, either the spigot end or the bell end ofsuch pipes includes a rubber seal which is compressed between the endsof the pipes to provide a sealed joint when the spigot end of one pipeis inserted into the bell end of another pipe. Occasionally, theseprimary joint seals between adjacent pipes may leak after installationin the field, requiring a secondary sealing assembly to seal theconnection.

Yet another application for sealing devices is in the upper openings ofmanhole systems, which typically facilitate access to the undergroundpipes from street level. For example, the manhole chimney and riserstructure may have seams through which ground water or other surroundingfluids can seep. In some cases, it is desirable to prevent the ingressof these ambient fluids through these seams in the manhole chimney.

One known sealing mechanism includes an expansion ring having aratcheting engagement between overlapping ends of the ring. When theends of the ring are forced in opposite directions from one another asthe ring is radially expanded, ratchet teeth on the ring endssequentially engage one another, wherein the expansion ring may besequentially expanded in an incremental manner into multiple lockedpositions. A separate tool is used to engage the opposite ends of theexpansion ring and to drive same apart from one another.

What is needed is an improved sealing assembly that can be installedwithin an annular opening, such as an opening in the wall of a manhole,to provide a reliable seal.

SUMMARY

The present disclosure provides a sealing assembly with an expansionband having an arcuate band portion and a pair of threaded end portionsformed at opposing ends of the arcuate band, in which the arcuate bandand threaded end portions are monolithically formed as a single piece.Fixed within respective threaded end portions are a pair of oppositelythreaded nuts adapted to receive a bolt having correspondinglyoppositely threaded ends. Rotation of the bolt causes the threaded endportions to be simultaneously driven apart or drawn toward one another(depending on the rotation direction of the bolt) to thereby expand orcontract the overall outer profile of the arcuate band portion. Themonolithically formed expansion band may be made of an inexpensive,non-rusting material such as nylon 66, and glass fibers and/or additivesmay be employed to impart strength and flexibility.

The sealing assembly of the present disclosure can be combined with aseal or gasket to provide a robust, cost-effective solution for sealinga connection between a concrete structure, such as a manhole wall, andan adjacent pipe entering or exiting the manhole wall. An alternativegasket/sealing assembly combination may be used for internally sealing aconnection between a pair of adjacent pipes. Yet another alternativegasket/sealing assembly combination may be used to sealing a connectionabout the upper end of a concrete structure, such as providing a sealacross a manhole frame and manhole chimney (as well as any interveningspacer rings therebetween).

In one form thereof, the present disclosure provides a sealing assemblyincluding: an expansion band having an arcuate band portion, a pair ofthreaded end portions monolithically formed with the arcuate bandportion and disposed at opposing ends of the arcuate band portion, apair of first threaded components having opposing threads andrespectively captured within the pair of threaded end portions, and asecond threaded component including oppositely-threaded endsrespectively threadably engaged with the pair of first threadedcomponents. Rotation of the second threaded component in a firstdirection causes the pair of threaded end portions to be simultaneouslydriven apart from one another to thereby expand a diameter of thearcuate band portion.

In another form thereof, the present disclosure provides a method ofmaking an expansion band, the method including: placing a pair ofoppositely-threaded first threaded components into a mold cavity, themold cavity shaped to create an expansion band having an arcuate bandportion, and a pair of end portions monolithically formed with thearcuate band portion and disposed at opposing ends of the arcuate bandportion. The method further includes: injecting a molten material intothe mold cavity, such that the molten material flows around the firstthreaded components and throughout the mold cavity, wherein the moltenmaterial forms the arcuate band portion and the pair of end portionswith the pair of oppositely-threaded first threaded componentsrespectively captured within the end portions when the molten materialhardens; and threadably engaging a second threaded component with thepair of oppositely-threaded first threaded components, the secondthreaded component having oppositely-threaded ends adapted tosimultaneously drive apart the pair of end portions to thereby expand adiameter of the arcuate band portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention itself will be better understood by reference to the followingdescriptions of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a perspective, partial section view of a connection between aconcrete structure and a pipe, wherein a wall of the concrete structureincludes an opening into which a gasket is sealingly fitted with asealing assembly according to the present invention, and further showinga pipe sealingly connected to the gasket;

FIG. 2 is a perspective view of a sealing assembly made in accordancewith the present disclosure;

FIG. 3 is a front elevation view of the sealing assembly of FIG. 2;

FIG. 4 is an enlarged, partial cross-sectional view of a portion of thesealing assembly shown in FIG. 2, shown in a contracted state;

FIG. 5 is an enlarged, cross-sectional view of a portion of the sealingassembly shown in FIG. 2, shown in an expanded state;

FIG. 6 is a top plan view of the sealing assembly of FIG. 2;

FIG. 7 is a bottom plan view of the sealing assembly of FIG. 2;

FIG. 8 is a side elevation view of the sealing assembly shown in FIG. 2,it being understood that left and right side views of the sealingassembly are identical;

FIG. 9A is a partial, exploded perspective view of the sealing assemblyshown in FIG. 2, illustrating an assembly of components which connect tothreaded end portions of the expansion band;

FIG. 9B is partial, exploded perspective view of an alternative sealingassembly made in accordance with the present disclosure;

FIG. 9C is a perspective view of an actuation bolt in accordance withthe present disclosure;

FIG. 10 is a perspective view of the sealing assembly of FIG. 2,illustrating attachment of the oversleeve to cover the threaded endportions;

FIG. 11 is a plan, cross-section view of an annular opening,illustrating the sealing assembly in a contracted configuration suitablefor initial placement of the gasket;

FIG. 12 is another plan, cross-sectional view of the annular openingshown in FIG. 11, in which the sealing assembly has been expanded intoan installed configuration seated against the gasket;

FIG. 13 is a cross-sectional view of an injection molding assemblysuitable for forming the expansion band of the sealing assembly shown inFIG. 2;

FIG. 14 is a perspective, cross-section view of a pipe-to-pipeconnection having a gasket contained therein, in which the gasket isheld in place by a pair of sealing assemblies in accordance with thepresent disclosure; and

FIG. 15 is a perspective, cross-section view of a manhole frame andmanhole base disposed beneath a pavement surface, in which a gasket isheld in place by a pair of sealing assemblies in accordance with thepresent disclosure.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate embodiments of the invention, and such exemplifications arenot to be construed as limiting the scope of the invention in anymanner.

DETAILED DESCRIPTION

1. Introduction

Referring now to FIG. 1, pipe connection assembly 100A in an undergroundpipe system is shown, in which pipe 130 is connected to a structure 132,such as a manhole riser or monolithic base, for example. Structure 132may be formed of concrete, fiberglass, or any other suitable rigidmaterial. Structure 132 includes wall 134 having interior surface 136defining the interior of structure 132, and exterior surface 138defining the exterior of structure 132. Additionally, wall 134 includesopening 104 formed therein. An annular seal or gasket 102A includes afirst portion 142 disposed within opening 104 of wall 134, and a secondportion 144 extending outwardly from first portion 142. Gasket 102A maybe made from a flexible, elastomeric material such as rubber orneoprene, for example, and provides a sealing connection between opening104 in wall 134 of structure 132 and pipe 130.

More particularly, first portion 142 of gasket 102A is sealingly engagedwith opening 104 of wall 134 by sealing assembly 20, which generallyincludes expansion band 22, bolt 30, and oversleeve 32 as described indetail below. Sealing assembly 20 is radially expandable to compressgasket 102A into sealing engagement with opening 104 in wall 134 toprovide a fluid tight seal therebetween. As shown in FIG. 2 anddescribed in further detail below, sealing assembly 20 includesexpansion band 22 having an arcuate band portion 24 and a pair ofthreaded end portions 26A, 26B which are monolithically formed as asingle material, such as a polymer material, to provide a resilient,effective and cost-effective solution for providing this fluid tightseal.

After first portion 142 (FIG. 1) of gasket 102A is sealingly engagedwith opening 104 of wall 134 by sealing assembly 20, second portion 144of gasket 102A is connected to pipe 130 by inserting pipe 130 throughgasket 102A, then installing one or more clamps 146 around secondportion 144 of gasket 102A and tightening clamps 146 to compress secondportion 144 of gasket 102A into sealing engagement with outer surface148 of pipe 130 to provide a fluid tight seal therebetween. Secondportion 144 of gasket 102A may include annular recessed seats 150 forreceipt of clamps 146 to locate clamps 146 on second portion 144 ofgasket 102A.

In FIG. 1, only a portion of the length of pipe 130 is shown forclarity, it being understood that pipe 130 typically extends pastsealing assembly 20 through opening 104 in wall 134, past interiorsurface 136 of wall 134, and into the interior of structure 132. Also,sealing assembly 20 as shown in FIG. 1 has threaded end portions 26A,26B and the associated components, including bolt 30, disposed in a nineo'clock position with respect to opening 104 for clarity. However, endportions 26A, 26B and bolt 30 may be positioned at any desired positionaround the circumference of opening 104, it being noted that aconfiguration with end portions 26A, 26B and bolt 30 disposed in atwelve o'clock position is favored in many applications to avoid orminimize contact with fluid. Further, the pipe connection of FIG. 1 mayinstalled in a manner in which second portion 144 of gasket 102A extendsinwardly from wall 134, in essentially the opposite manner shown in FIG.1, such that clamps 146 are disposed within structure 132.

Optionally, first portion 142 of gasket 102A may include an annularexpansion band seat (not shown in FIG. 1), similar to expansion bandseats 110 shown in FIGS. 14 and 15 and further described below, toprovide an annular recessed area to receive expansion band 22 andoversleeve 32 upon creating the sealed connection between first portion142 of gasket 102A and the inner annular surface of opening 104.

2. Sealing Assembly Construction

Turning now to FIG. 2, a perspective view of sealing assembly 20 isshown in a contracted configuration that is ready for installation at aservice site. Sealing assembly 20 includes expansion band 22, which hasan arcuate band portion 24 forming a generally cylindrical outer shapeand a corresponding circular profile (FIG. 3), and threaded end portions26A, 26B formed at respective opposing ends of arcuate band portion 24.As used herein, “cylindrical” refers to a shape or structure generallyconforming to the shape of a cylinder, it being understood that preciseconformance thereto is not necessary for a structure to be considered“cylindrical.” For example, an expansion band made in accordance withthe present disclosure may be an injection molded part that isconsidered to be substantially cylindrical in both expanded andcontracted configurations, even though one of such configurations may beslightly oblong (e.g., oval or egg shaped as described further below).

Bolt 30 is threadably received within nuts 28A, 28B, which are capturedwithin end portions 26A, 26B (shown in FIGS. 4 and 5, and describedbelow). In this manner, bolt 30 connects and affixes end portions 26A,26B to one another. Oversleeve 32 is received upon an outer surface ofexpansion band 22 and has a longitudinal, arcuate span whichsubstantially covers both of threaded end portions 26A, 26B and spans agap 34 between end portions 26A, 26B (FIG. 10). Although gap 34 formedbetween end portions 26A, 26B interrupts the overall circular profile ofexpansion band 22, continuity of the circular profile is provided by thecorrespondingly curved profile of oversleeve 32.

Expansion band 22 is monolithically formed as a single piece of uniformmaterial throughout its volume, including both arcuate band portion 24and threaded end portions 26A, 26B. In one exemplary embodiment,expansion band 22 may be formed by injecting a flowable (e.g., molten)material into a cavity of a mold, as shown in FIG. 13 and furtherdescribed below.

As illustrated in FIGS. 4 and 5, the material used to form expansionband 22 is sufficiently flexible to allow sealing assembly 20 to bereconfigured between expanded and contracted states. Such expansion andcontraction is further described below with reference to FIGS. 9A and10. At the same time, the material of expansion band 22 possessessufficient strength and rigidity to impart a significant radial outwardforce upon an adjacent gasket, such that the gasket creates a liquidtight engagement with an adjacent annular inner wall of a pipe orstructure. In one exemplary embodiment, the material used to createexpansion band 22 is nylon 66, 33% glass filled, and includes up to 1%by weight of an additive operable to increase the flexural modulus ofthe material. An exemplary additive material may be any polymer addableto the nylon 66 which results in a flexural modulus for expansion band22 which may be as little as 0.290 GPa, 0.950 GPa, 3.0 GPa or 3.105 GPaand as much as 5.780 GPa, 7.0 GPa, 8.250 GPa or 13.5 GPa. It iscontemplated that the flexural modulus of expansion band 22 may have anyvalue within any range defined by any of the foregoing values, dependingon the particular application. In one particular exemplary embodiment,the flexural modulus defined by expansion band 22 may be about 4.5 GPa.In another exemplary embodiment, Young's modulus for expansion band 22may be between 3.0 GPa and 6.0 GPa.

In one particular embodiment, sealing assembly 20 is designed for useinside an aperture (such as opening 104 shown in FIGS. 11 and 12) havinga nominal 12-inch inside diameter. In this application, the effectiveoutside diameter D_(C), i.e., the diameter of the cylindrical outersurface of expansion band 22 in its contracted state, is about 11.2inches, which allows sealing assembly 20 to be placed into an 11.5-inchdiameter opening (i.e., the diameter of a 12-inch opening 104, less theradial space taken up by a ¼-inch-thick gasket 102, as shown in FIG.11). For the exemplary nylon 66, 33% glass filled, additive-enhancedmaterial described above, a material thickness T (FIG. 3) for arcuateband portion 24 equaling about 0.24 inches is capable of imparting asufficient radial outward sealing force to create a liquid tight seal,which also allows sealing assembly 20 to deform sufficiently uponinstallation to take the form of the adjacent sealing surface of thepipe or manhole opening.

When expanded, sealing assembly 20 has an expanded outside diameterD_(E) (FIG. 12) of about 11.55 inches, which is slightly larger than the11.5 inch opening in gasket 102 as assembled in opening 104. Thus, whensealing assembly 20 is installed into opening 104, the oversizedexpanded diameter D_(E) compresses gasket 102 and creates acorresponding liquid tight seal between gasket 102 and opening 104.

Upon expansion of sealing assembly 20 from its contracted state to itsexpanded state, gap 34 is made larger by actuation of bolt 30 asdescribed further below. In the contracted state, the respectiveterminal end surfaces 29A, 29B of threaded end portions 26A, 26B areseparated by contracted gap distance G_(C) (FIG. 4), while in theexpanded state this distance increases to expanded gap distance G_(E)(FIG. 5). For the above-described embodiment of sealing assembly 20designed for opening 104 having a 12-inch diameter, contracted distanceG_(C) is about 0.5 inches and expanded distance G_(E) is about 1.67inches.

As best seen in FIGS. 2 and 3, arcuate band portion 24 and threaded endportions 26A, 26B are monolithically formed as a single part withthreaded end portions 26A, 26B disposed at opposing ends of arcuate bandportion 24. The material of end portions 26A, 26B progressively thickensstarting at the respective junctions between arcuate band portion 24 andend portions 26A, 26B and advancing toward the terminal end surfaces29A, 29B of expansion band 22. When viewed in profile as shown in FIG.3, this thickening causes the interior profile of end portions 26A, 26Bto transition from the generally circular shape of the inner diameter ofarcuate band portion 24 to the flat and linear profile of end portions26A, 26B. This flat profile defines chord line 27 extending across aportion of the otherwise circular profile of sealing assembly 20. Whenviewed from above as shown in FIG. 3, i.e., with a line of sight alonglongitudinal axis A (FIG. 2) of sealing assembly 20, the progressivelythickened material of end portions 26A, 26B is completely containedwithin the overall circular outer profile defined by expansion band 22and oversleeve 32, thereby maintaining the cylindrical outer profile ofsealing assembly 20.

Turning to FIGS. 4 and 5, the progressive thickening of the material ofexpansion band 22 in the vicinity of threaded end portions 26A, 26Bfacilitates the inclusion of bores 36A, 36B therethrough, respectively.Bores 36A, 36B (FIGS. 4 and 5) extend substantially parallel to chordline 27 and are disposed radially inwardly of the cylindrical outersurface of expansion band 22, and are sized to receive threaded portions42, 44 of bolt 30. Chord line 27 is radially spaced inwardly from theouter cylindrical surface of sealing assembly 20 by a sufficient amountto ensure that a material thickness commensurate of thickness T ofarcuate band 24 (FIG. 3) is maintained in the vicinity of bores 36A, 36Band throughout threaded end portions 26A, 26B. At the same time, theradial inward spacing of chord line 27 is kept to a low enough level toavoid excessive protrusion of end portions 26A, 26B into the otherwisecircular opening of expansion band 22 and to avoid excessive materialthickness in end portions 26A, 26B. This balanced inward spacing ofchord line 27 provides an overall flexural modulus in the materialaround bores 36A, 36B that is commensurate with arcuate band portion 24,thereby promoting consistent distribution of radial outward force whensealing assembly 20 is installed (as described below).

FIG. 2 illustrates that the built-up material at threaded end portions26A, 26B has a substantially circular cross-section to create asubstantially uniform material thickness around each of bores 36A, 36Band nuts 28A, 28B. However, to avoid stress risers resulting from anysharp material corners, the built-up material transitions smoothly fromthe round cross-section around bores 36A, 36B to the substantiallyrectangular cross-section at the radially outward area of end portions26A, 26B. These radially outward areas are shaped as continuations ofarcuate band portion 24, and maintain the overall cylindrical outerprofile of expansion band 22. The radially inward, thickened areasforming threaded end portions 26A, 26B and defining chord line 27 (FIG.3) provide structural support for the expansion functionality of sealingassembly 20.

Nuts 28A, 28B are captured within bores 36A, 36B, respectively. As bestillustrated in FIGS. 4 and 5, nuts 28A, 28B are disposed flush torespective terminal end surfaces 29A, 29B of threaded end portions 26A,26B. In addition, the threaded bores formed in nuts 28A, 28B are axiallyaligned with one another, such that longitudinal axis A_(N) of bolt 30coincides with the corresponding longitudinal axes of the threaded boresof nuts 28A, 28B when bolt 30 is threadably received therewithin asillustrated. Additionally, bores 36A, 36B define longitudinal axes whichare coaxial with bolt axis A_(N) when sealing assembly 20 is assembledas shown. This mutual coaxiality of nuts 28A, 28B, bores 36A, 36B, andbolt 30 is maintained regardless of whether sealing assembly 20 isconfigured in the contracted state (FIGS. 4 and 11) or the expandedstate (FIGS. 5 and 10).

Bolt 30 includes a centrally located, hex-shaped wrench engagementportion 38 engageable with wrench 41 (FIG. 5) to turn bolt 30 to expandand contract sealing assembly 20, as described below. In one embodiment,wrench engagement portion 38 may be flanked at each axial end thereof bywrench containment flats 40, which impose a physical barrier to axialsliding of wrench 41 along axis A_(N) and thereby prevent wrench 41 fromsliding axially off of engagement portion 38. Right-hand threadedportion 44 of bolt 30 extends axially away from one of containment flats40 and into right-hand threaded nut 28B, while left-hand threadedportion 42 of bolt 30 extends axially away from the other of containmentflats 40 and into left-hand threaded nut 28A. In an exemplaryembodiment, bolt 30 may be formed from 304 stainless steel, whichinhibits corrosion in potentially damp environments during service ofsealing assembly 20.

In another exemplary embodiment shown in FIG. 9B, bolt 30A may beprovided. Bolt 30A is similar to bolt 30 described herein, withstructures of bolt 30A having reference numerals analogous to referencenumerals used to describe analogous structures of bolt 30, except with“A” appended thereto. However, bolt 30A omits wrench containment flats40, and instead providing wrench 41A having side shields 40A sized andpositioned to be received at either end of wrench engagement portion38A. When so engaged, wrench 41A cannot move axially with respect tobolt 30A. This embodiment may allow for a larger overall size of wrenchengagement portion 38A of bolt 30A.

Referring now to FIG. 9C, bolt 30A may also include recess 52 formed inthe terminal axial end surface of right-hand threaded portion 44. Recess52 is accessible via bores 36B by a tool (not shown), such that the toolcan be received in recess 52 and used to rotate bolt 30A in a desireddirection. In the illustrated embodiment, recess is hex-shaped and sizedto receive an allen wrench. For the exemplary embodiment of sealingassembly 20 useable with 12-inch diameter opening 104, recess 52 mayhave a dimension across opposing flats of 3/16 inches and an axial depthof 3/16 inches, which in turn minimizes or eliminates any weakening ofbolt 30A while providing sufficient size and depth for engagement by acorrespondingly sized wrench. In other embodiments, recess may haveother shapes such as square, star-shaped, slotted or crosshead, asrequired or desired for a particular design. Recess 52 facilitatesassembly of seal assembly 20, as further described below.

When wrench 41 (or wrench 41A) is rotated in a first direction, bolt 30(or bolt 30A) simultaneously threads outwardly from both right-hand nut28B and left-hand nut 28A, thereby spreading threaded end portions 26A,26B apart from one another and widening gap 34 as shown by a comparisonof FIGS. 4 and 5. Conversely, if wrench 41 (or wrench 41A) is rotated ina second, opposite direction, right-hand and left-hand threaded portions44, 42 of bolt 30 (or bolt 30A) are threaded further into nuts 28A, 28B,respectively, thereby advancing threaded end portions 26A, 26B towardone another and shrinking gap 34. As described in detail below, theexpansion of gap 34 is employed during installation of sealing assembly20.

As illustrated in FIG. 4, threaded portions 42, 44 of bolt 30 aresufficiently short to be fully contained within bores 36A, 36B,respectively, even when sealing assembly 20 is in the fully contractedconfiguration of FIG. 4, thereby ensuring that the cylindrical outerprofile of expansion band 22 is not disrupted by protrusion of threadedportions 42, 44 outwardly from bores 36A, 36B. Concomitantly, bores 36A,36B are designed with sufficient axial length to receive the full axiallength of threaded portions 42, 44 of bolt 30, respectively. The axiallengths of bores 36A, 36B are set by positioning bores 36A, 36Bsufficiently radially inwardly (i.e., toward longitudinal axis A of FIG.2), which also facilitates maintaining a desired material thickness inthreaded end portions 26A, 26B as noted above. In the illustratedembodiment suitable for sealing 12-inch diameter openings 104,longitudinal axis A_(N) of bolt 30 is radially inset by an insetdistance D_(I) (FIGS. 4 and 5) of about 0.43 inches from the outercylindrical surface defined by expansion band 22.

In an exemplary embodiment, nuts 28A, 28B are made from a 304 stainlesssteel material, which inhibits corrosion as noted above. Nuts 28A, 28Bmay also have a knurled outer surface to facilitate firm capture withinbores 36A, 36B, respectively, during molding of expansion band 22(described further below). In addition to knurling, one or more radialfins (not shown) may be formed on nuts 28A, 28B for additional axialfixation within the molded material of threaded end portions 26A, 26B.Further, as best seen in FIGS. 4 and 5, the outer perimeter of nuts 28A,28B is larger than the inner diameter of bores 36A, 36B, therebycreating a shoulder which inhibits axial movement of nuts 28A, 28Bfurther into bores 36A, 36B respectively. The axial forces placed onnuts 28A, 28B during service of sealing assembly 20 are directedoutwardly from bores 36A, 36B, because expansion band 22 is forcedoutwardly to create a radially outward, compressive force on a gasket.Thus, the shoulders created in bores 36A, 36B operate to inhibit axialmovement of nuts 28A, 28B during normal use of sealing assembly 20.

As an alternative to the arrangement of bolt 30 and nuts 28A, 28Bdescribed above, it is contemplated that the male and female threadedstructures of sealing assembly 20 (i.e., threaded portions 42, 44 ofbolt 30 and the correspondingly threaded bores of nuts 28A, 28Brespectively) may be reversed. That is to say, rather than capturingnuts 28A, 28B within threaded end portions 26A, 26B of expansion band 22as shown in the figures and described above, it is contemplated thatoppositely threaded studs may be captured within and extend outward fromthreaded end portions 26A, 26B. In this alternative arrangement, afemale threaded elongated nut, tube or standoff havingoppositely-threaded inner bores at respective opposite axial endsthereof is threadably received on the studs, such that rotation of thefemale nut, tube or standoff either expands or contracts gap 34 insimilar fashion to sealing assembly described above.

Turning now to FIGS. 9A and 10, oversleeve 32 may be received overexpansion band 22 in the vicinity of threaded end portions 26A, 26B toprovide continuity of the cylindrical outer surface of expansion band22. As best seen in FIG. 10, oversleeve 32 has a sufficient arcuatelength to completely span and cover gap 34, as well as cover bore 36Aand bore 36B. As shown in FIG. 9A, oversleeve 32 has a shallow U-shapedprofile corresponding to the generally rectangular profile of arcuateband portion 24 (and the similarly-shaped radially outward areas ofthreaded end portions 26A, 26B). In order to promote an overall uniformouter surface of sealing assembly 20 while accommodating oversleeve 32,end portions 26A, 26B each include steps 46 to reduce the axial extentof expansion band 22 to compensate for the thickness of sidewalls 48 ofoversleeve 32. Optionally, the profile of the radial outward surface ofthreaded end portions 26A, 26B may be similarly stepped to accommodatebase portion 50 of oversleeve 32, though in some applications such astep may not be necessary to provide an effective seal.

In the alternative embodiment shown in FIG. 9B, oversleeve 32A may beprovided. Oversleeve 32A is similar to oversleeve 32 described herein,with structures of oversleeve 32A having reference numerals analogous toreference numerals used to describe analogous structures of oversleeve32, except with “A” appended thereto. However, oversleeve 32A includes apair of material augmentations 33 spanning the angular junction betweeninside surface 51A of base portion 50A and the inwardly-facing surfacesof respective sidewalls 48A. As illustrated, augmentations 33 define aconvex, curved surface extending from the radial inward surface 49A ofeach sidewall 48 to inside surface 51A of base portion 50A.

In an exemplary arrangement, augmentations 33 are disposed at about themiddle of oversleeve 32A (i.e., equidistant from the circumferentialends of oversleeve 32A). When assembled to expansion band 22 asillustrated, augmentations 33 occupy the space between respectiveterminal end surfaces 29A, 29B of threaded end portions 26A, 26B. Tofacilitate this, augmentations define width W that is equal to or lessthan contracted gap distance G_(C) between end portions 26A, 26B (FIG.4). Thus, augmentations provide a rib-like structure that stiffens andstrengthens oversleeve 32A, while remaining spatially compatible withexpansion band 22 to form a part of sealing assembly 20.

Further detail regarding certain exemplary embodiments of bolt 30 andoversleeve 32 can be found in U.S. Pat. Nos. 6,805,359 and 7,146,689,each assigned to the assignee of the present invention, the entiredisclosures of which are expressly incorporated herein by reference.

3. Sealing Assembly Use

Turning now to FIG. 11, sealing assembly 20 is illustrated in aninitially-installed position adjacent gasket 102 and within opening 104.Sealing assembly 20 is in the contracted configuration, thereby leavingan annular gap between the cylindrical outer surface of expansion band22 and the corresponding cylindrical inner surface of expansion bandseat 110 of gasket 102. In addition, the outer cylindrical surface ofgasket 102 is shown to be spaced slightly from the inner cylindricalsurface of opening 104. This radial spacing facilitates easy passage ofgasket 102 and sealing assembly 20 into opening 104 for initialpositioning.

Once the installer is satisfied with the position and configuration ofgasket 102 and sealing assembly 20 with respect to opening 104, bolt 30is actuated to reconfigure sealing assembly 20 into the expandedconfiguration of FIG. 12. As noted above, actuation of bolt 30 isaccomplished by engaging wrench 41 (FIG. 5) with wrench engagementportion 38 of bolt 30 and rotating wrench 41 along direction R. Thisrotation advances threaded portions 42, 44 simultaneously outwardly fromnuts 28A, 28B, respectively, thereby spreading threaded end portions26A, 26B apart from one another. The resulting increase in the size ofgap 34 from spacing G_(C) to spacing G_(E) (FIGS. 4 and 5) effectivelyexpands the overall diameter of expansion band 22 from contracteddiameter D_(C) (FIG. 11) to expanded diameter D_(E) (FIG. 12), therebyeliminating the annular gaps between the outer cylindrical surface ofexpansion band 22 and the adjacent inner surface of gasket 102, as wellas the gaps between the outer cylindrical surface of gasket 102 and theadjacent inner surface of opening 104.

When sufficient radial outward force is applied by expansion band 22upon gasket 102, a fluid tight seal is effected between sealing assembly20 and gasket 102, and between gasket 102 and opening 104. As notedabove, in order to maintain a consistent radial outward force in thevicinity of end portions 26A, 26B when bolt 30 is tightened, oversleeve32 is provided prior to installation of sealing assembly 20 to provide aconsistent cylindrical outer surface of sealing assembly 20. In theillustrated exemplary embodiment, 20 foot-pounds of torque applied tobolt 30 is sufficient to create a fluid tight seal around the entireperiphery of sealing assembly 20.

In an exemplary embodiment, expansion band 22 is designed to be nearlyexactly cylindrical and substantially free of internal stresses when inthe contracted configuration of FIG. 11. This cylindrical profile in thecontracted state facilitates installation of sealing assembly 20 intothe confined space of opening 104, obviating any need to manuallyreshape any portion of expansion band 22 during initial placement ofsealing assembly 20 and gasket 102. When sealing assembly 20 issubsequently reconfigured to the expanded state shown in FIG. 12, nuts28A, 28B and bores 36A, 36B maintain coaxiality with longitudinal axisA_(N) of bolt 30 as noted above. This maintained coaxiality, togetherwith the expansion of the overall diameter of expansion band 22,propagates stresses into the material of expansion band 22. Thesestresses are greatest near the junction of arcuate band 24 and therespective end portions 26A, 26B, and therefore tend to urge the outerperiphery of expansion band 22 into a slightly noncylindrical shape witha generally oblong or egg-shaped outer profile. However, as also notedabove, the material and thickness of expansion band 22 is designed tobend and flex under pressure. The rigid inner surface of opening 104,which is typically substantially cylindrical, urges expansion band 22back into a cylindrical shape as expansion band 22 expands.

Advantageously, the flexibility and pliability of the material fromwhich expansion band 22 is formed facilitates the ability of expansionband 22 to retain its cylindricity under the pressures applied to itwhen expanded within opening 104. Stated another way, expansion band 22is sufficiently pliable to react to the stresses imposed by expansion ofsealing assembly 20 (and the opposing stresses exerted by the interiorwall of opening 104) by conforming to the cylindrical inner profile ofthe opening to be sealed. This pliability ensures a fluid tight sealbetween sealing assembly 20 and gasket 102, and between gasket 102 andopening 104.

4. Expansion Band Manufacture

In an exemplary embodiment, expansion band 22 is monolithically formedas a single part by an injection molding process. Turning to FIG. 13,mold 200 adapted for such a process is illustrated in cross-section.Mold 200 includes cavity 202 which corresponds to the overall shape anddimensions of expansion band 22, except that cavity 202 is slightlylarger than expansion band 22 to accommodate for material shrinkage asexpansion band 22 cools after production. To create expansion band 22,molten or otherwise flowable material is injected into cavity 202 untilcavity 202 is completely filled, and the material within cavity 202 isthen allowed to slowly cool until hardened into expansion band 22. Onthe left-hand side of FIG. 13, mold 200 is shown ready to receive aninjection of flowable material, while the right-hand side shows mold 200after such flowable material has been injected and allowed to cool.

Mold 200 includes nut installation mechanisms 204, 205 which facilitatethe inclusion of nuts 28A, 28B, respectively, during the injectionmolding process. When the flowable material is injected into cavity 202,the material flows around nuts 28A, 28B and, when hardened, capturesnuts 28A, 28B within threaded end portions 26A, 26B. Each of mechanisms204, 205 includes movable rod 206, which are axially movable by a smallamount within rod holder 208. In one exemplary embodiment, rods 206 areaxially movable with respect to rod holder 208 by 0.017 inches. Withintheir movable range, rods 206 are urged by springs 210 inwardly towardone another, and toward central block 212.

Prior to injecting molten and/or flowable material into cavity 202, nuts28A, 28B are installed on respective movable rods 206. As illustrated,rods 206 include stepped down portion 214 sized to accommodate nuts 28A,28B. Rods 206 are then moved into a molding position, in which nuts 28A,28B are held in abutting relationship against central block 212 as shownon the left-hand side of FIG. 13. Because stepped down portion 214 isaxially shorter than the axial extent of the threaded bores of nuts 28A,28B, springs 210 urge each of nuts 28A, 28B into firm and consistentcontact with central block 212.

Upon injection of molten material into cavity 202, such molten materialflows around nuts 28A, 28B and into contact with central block 212,thereby creating gap 34 (FIG. 2) of expansion band 22. However, becausenuts 28A, 28B are held into firm contact with central block 212, moltenmaterial does not flow around the axial end surface of nuts 28A, 28B incontact with central block 212. This arrangement creates a clean andflush surface including both the axial ends of nuts 28A, 28B and theterminal end surfaces 29A, 29B of threaded end portions 26A, 26B,respectively. Moreover, because the axial position of nuts 28A, 28B canbe tightly controlled by interaction between mechanisms 204, 205 andcentral block 212, the relative axial and spatial arrangement of thethreaded bores of nuts 28A, 28B may be similarly precisely controlled,thereby ensuring proper thread alignment when bolt 30 is installed aftermolding. Once expansion band 22 has hardened, rod holders 208 can beretracted, thereby withdrawing rods 206 from the newly formed bores 36A,36B while leaving nuts 28A, 28B in place as illustrated on theright-hand side of FIG. 13. Expansion band assembly can then be removedfrom cavity 202.

In an exemplary embodiment, bolt 30A including recess 52 may be used tofacilitate installation thereof into the finished molded expansion band22, by allowing a wrench to be received in bore 36B and quickly spun toseat bolt 30A within nuts 28A, 28B. Alternatively, it is contemplatedthat bolt 30 may be threadably received within nuts 28A, 28B prior tothe injection of molten material into cavity 202. In this instance, bolt30 is fully received into nuts 28A, 28B (as shown in FIG. 4) prior toinjection, so that expansion band 22 can be molded in the contractedconfiguration as noted above. Bolt 30 may pass through central block212, thereby preventing the flowable molten from contacting bolt 30.Upon completion of the molded expansion band 22 with bolt 30 attached,oversleeve 32 is attached to expansion band 22 at threaded end portions26A, 26B to complete sealing assembly 20.

Sealing assembly 20, made in accordance with the foregoing, provides alow cost yet highly effective sealing assembly for inner annularsurfaces of pipes, manholes or other annular structures. In addition,using molded materials such as polymers for expansion band 22 provides anon-rusting and non-degrading material for the harsh environments wheresealing assembly 20 may be used. This low cost, corrosion resistantassembly may also provide fluid tight seals of comparable strength tosimilar arrangements made entirely of metal, particularly where materialselection, material thickness, and overall part dimensions aremaintained on a scale approximately in accordance with the foregoingdisclosure. Accordingly, it is appreciated that sealing assembly 20 maybe scaled up or scaled down evenly to accommodate applications in largeror small openings 104.

5. Alternative Sealing Assembly Applications

Although sealing assembly 20 is shown in FIG. 1 in an application usedto secure gasket 102A within opening 104 in wall 134 of structure 132,sealing assembly 20 may also be used in many other applications.Moreover, the principles of the present design may be applied in anycontext in which a flexible structure is needed to impart a radialoutward force upon an adjacent surface by selectively expanding theflexible structure.

FIGS. 1, 14 and 15 respectively illustrate three potential applicationsfor sealing assembly 20, including underground pipe systems andmanholes. Each of these applications has a unique gasket 102A, 102B or102C used in conjunction with sealing assembly 20 to effect afluid-tight seal between an inner annular opening 104 and the adjacentmaterial of gasket 102. For purposes of the present disclosure, “gasket102” refers generically to any of gaskets 102A, 102B or 102C. Similarly,“opening 104” is used throughout the following descriptions, it beingunderstood that opening 104 can take on a variety of sizes andconfigurations within the scope of the present disclosure. Moreover,sealing assembly 20 may be used in any application which generallyinvolves the radial expansion of a flexible seal or gasket into sealingengagement with a rigid structure. The application illustrated in FIG. 1is discussed in detail above. The details and operation of sealingassembly 20 in two alternative applications are discussed below.

Turning to FIGS. 14 and 15, a pair of sealing assemblies 20 are shownsealingly attaching respective axial ends of gaskets 102B, 102C tocreate a fluid-tight seal in pipe assembly 100B (FIG. 14) or manholeassembly 100C (FIG. 15). In the illustrated embodiments, generallycylindrically shaped gaskets 102B and 102C each include a pair ofaxially spaced sealing portions 106 connected by a bridge portion 108.Bridge portion 108 may include one or more undulations as shown in orderto permit movement of sealing portions 106 toward and away from oneanother along their common axis, i.e., a longitudinal axis passingthrough the center of gasket 102B, 102C. Gaskets 102B, 102C may be madeof extruded rubber, for example, in a manner in which a length of rubbersection is extruded, and then is cut to a predetermined length, followedby splicing the ends of the section together to form the cylindricalgasket 102B or 102C. Gaskets 102B, 102C may also be made of a resilientplastic material by an injection molding process, for example.

Referring to FIG. 14, gasket 102B may be used with pipe assembly 100B toseal a defective primary seal in a pipe-to-pipe connection between pipesections 112 and 114, such as the connection between spigot end 116 ofpipe 112 and socket end 118 of pipe 114 in which a primary seal 120 isineffective. Yet another alternative is to use sealing assemblies 20with gasket 102 as a primary seal to seal pipe sections 112 and 114 uponinitial connection and installation thereof, or to seal across a crackin pipes 112 and/or 114.

Gasket 102B is placed within the pipes 112 and 114 such that one sealingportion 106 is positioned adjacent spigot end 116 of pipe 112 and theother sealing portion 106 is positioned adjacent socket end 118 of pipesection 114, with bridge portion 108 of gasket 102B bridging the gapbetween pipe sections 112 and 114. Thereafter, sealing assemblies 20 areplaced within respective expansion band seats 110 of gasket 102B, andbolts 30 of sealing assemblies 20 are actuated in the manner describedabove to outwardly radially compress sealing portions 106 into fluidtight sealing engagement with the inner surfaces of pipes 112, 114,respectively, thereby providing a fluid tight seal between pipes 112 and114. After gasket 102B is so sealingly engaged with pipes 112 and 114,fluid can flow through opening 104 without causing fluid pressure andpotential leakage at primary seal 120.

Referring to FIG. 15, a pair of sealing assemblies 20 are used to securegasket 102C about an interface between manhole base 124 and a manholeframe 126 disposed beneath pavement surface 128. Specifically, an uppersealing assembly 20 is used to press an upper expansion band seat 110 ofgasket 102C into sealing engagement with manhole frame 126, and a lowersealing assembly 20 is used to press a lower expansion band seat 110 ofgasket 102C into sealing engagement with manhole base 124. In thismanner, water infiltration into manhole base 124 is prevented,regardless of whether relative movement occurs between manhole frame 126and manhole base 124.

While this disclosure has been described as having exemplary designs,the present disclosure can be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the disclosure using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this disclosure pertains and which fallwithin the limits of the appended claims.

1-20. (canceled)
 21. A method of making an expansion band, the methodcomprising: placing a pair of oppositely-threaded first threadedcomponents into a mold cavity, the mold cavity shaped to create anexpansion band comprising: an arcuate band portion; and a pair of endportions monolithically formed with the arcuate band portion anddisposed at opposing ends of the arcuate band portion; and injecting amolten material into the mold cavity, such that the molten materialflows around the first threaded components and throughout the moldcavity, wherein the molten material forms the arcuate band portion andthe pair of end portions with the pair of oppositely-threaded firstthreaded components respectively captured within the end portions whenthe molten material hardens.
 22. The method of claim 21, furthercomprising the additional step of threadably engaging a second threadedcomponent with the pair of oppositely-threaded first threadedcomponents, the second threaded component having oppositely-threadedends adapted to simultaneously drive apart the pair of end portions tothereby expand a diameter of the arcuate band portion.
 23. The method ofclaim 22, wherein said step of threadably engaging the second threadedcomponent with the pair of oppositely-threaded first threaded componentsis performed after said step of injecting the molten material into themold cavity.
 24. The method of claim 21, wherein the expansion banddefines a contracted state when the molten material hardens, theexpansion band having a substantially cylindrical outer profile in thecontracted state.
 25. The method of claim 21, wherein said step ofplacing the pair of oppositely-threaded first threaded components intothe mold cavity comprises spring-biasing each of the pair ofoppositely-threaded first threaded components toward a central block,wherein respective axial ends of the pair of oppositely-threaded firstthreaded components are maintained flush with respective terminal endsof the pair of end portions after said step of injecting the moltenmaterial.
 26. The method of claim 25, wherein said step ofspring-biasing each of the pair of oppositely-threaded first threadedcomponents comprises placing each first threaded component onto an endof a moveable rod, the moveable rod transmitting spring force to arespective first threaded component.
 27. The method of claim 26, whereinsaid step of injecting the molten material comprises allowing the moltenmaterial to flow around each moveable rod to form a pair of boresthrough the pair of end portions.
 28. The method of claim 22, wherein atleast one of the pair of end portions includes a bore, the bore defininga longitudinal bore axis coaxial with a longitudinal component axis ofthe second threaded component when the second threaded component isthreadably engaged with the pair of first threaded components.
 29. Themethod of claim 28, further comprising the steps of: engaging a toolwith a tool engagement fitting on an end of the second threadedcomponent through an end of the bore which extends to an outermostsurface of the band; and rotating the second threaded component with thetool to threadably engage the second threaded component with theoppositely-threaded first threaded components.
 30. The method of claim28, wherein each of the pair of end portions includes a bore, each ofthe bores including a shoulder formed therein, and each of the pair offirst threaded components are captured within a respective one of thebores such that respective first axial ends of the pair of firstthreaded components each abut a respective one of the shoulders.
 31. Themethod of claim 21, wherein each of the pair of end portions includes abore, the bores respectively receiving the oppositely-threaded firstthreaded components.
 32. The method of claim 31, wherein an axial end ofeach of the pair of first threaded components is flush with a respectiveterminal end surface of a respective end portion.
 33. The method ofclaim 31, wherein respective material thicknesses defined by the pair ofend portions are substantially constant around each of the bores,whereby the pair of end portions have a smooth and rounded outersurface.
 34. The method of claim 31, wherein an overall flexural modulusof the material around each of the bores is commensurate with a flexuralmodulus of the arcuate band portion, whereby consistent distribution ofradial outward force is promoted when the expansion band is installed.35. The method of claim 21, wherein the arcuate band portion defines acircular shape as viewed in profile, and the pair of end portionscooperate to define a substantially linear surface intersecting thecircular shape of the arcuate band portion, as viewed in profile. 36.The method of claim 35, wherein the substantially linear surface definesa chord line and the bores of the pair of end portions define a commonlongitudinal axis, the chord line substantially parallel to thelongitudinal axis.
 37. The method of claim 21, wherein a profile of eachof the pair of end portions progressively radially thickens from asubstantially rectangular cross-section starting at respective junctionsbetween the arcuate band portion and the pair of end portions andadvancing toward a substantially round cross-section at respectiveterminal end surfaces of the expansion band.